The mechanisms of many neural development and regeneration are currently unclear; studies in model organisms such as C. elegans may elucidate these mechanisms. C. elegans are a well known, commonly used model system because of its sequenced genome, simple nervous system, and the availability of many mutants and molecular reagents. Understanding how neurons polarize and guide axons to their targets in C. elegans can therefore shed light on these complex processes in higher organisms. Studying these mechanisms using current technologies, however, is difficult. Performing phenotypic screens of animals is generally a manual process, and worms with subtle phenotypic expression further confound the issue, miting advancement of C. elegans research. The long-term goal in C. elegans research is to discover how genes and neural activity ultimately affect behavior. While traditional genetics has made large contributions to this field, it is limited in throughput and subject to human bias. The proposed work will advance current research by designing a microfluidic system for high-throughput and automated phenotypic screens of neuronal polarity and axon guidance mutants. The device will increase throughput of genetic screens and will reduce human bias by using software for phenotypic analysis. To achieve this goal, we will improve methods for imaging and sorting worms in microfluidic devices. In parallel, we will develop image analysis software capable of quantifying characteristics of specific neuronal features. To validate the proposed technology, we will screen for novel mutants using fluorescent markers. The proposed work is significant because it can dramatically increase current capabilities of screening small animals with subtle fluorescent phenotypes. The project will also advance neural development research by discovering novel mutants and investigating new pathways. The proposed project will not only be beneficial to the scientific community in general, but also to the training and development of a young researcher. With the ability to analyze numerous C. elegans genotypes, this technology is relevant to many fields. In general, understanding the mechanisms behind behavior in any organism will help to further explain the mysteries of the human brain and potentially aid in the discovery of therapeutic treatments for various diseases.